Fix preload tests failing on wpt.fyi dashboard

verifyNumberOfDownloads only counts resource timing entries with
transferSize > 0, so it doesn't count if the resource came from a cache.
(See https://bugzilla.mozilla.org/show_bug.cgi?id=1222633#c38 for
background why we have it.)

link-header-preload-nonce.html and link-header-preload-srcset.tentative.html
were failing on wpt.fyi dashboard because they have used the same
subresource URLs as other tests, and preloaded resources from the disk
cache.

This patch adds unique query parameters to these URLs so that they don't
conflict with other tests.

Bug: 922343
Change-Id: I7fd88530f5fdd83ed2a22d2e2893cc446debd036
Reviewed-on: https://chromium-review.googlesource.com/c/1411963Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Commit-Queue: Kunihiko Sakamoto <ksakamoto@chromium.org>
Cr-Commit-Position: refs/heads/master@{#623157}

third_party/blink/web_tests/external/wpt/preload/link-header-preload-nonce.html

@@ -9,8 +9,8 @@
 <script nonce="abc">
     window.addEventListener('load', t.step_func(function() {
         verifyPreloadAndRTSupport();
-        verifyNumberOfDownloads("resources/dummy.js?without-nonce", 0);
-        verifyNumberOfDownloads("resources/dummy.js?with-nonce", 1);
+        verifyNumberOfDownloads("resources/dummy.js?from-header&without-nonce", 0);
+        verifyNumberOfDownloads("resources/dummy.js?from-header&with-nonce", 1);
         t.done();
     }));
 </script>

third_party/blink/web_tests/external/wpt/preload/link-header-preload-nonce.html.headers

 Content-Security-Policy: script-src 'nonce-abc'
-Link: </preload/resources/dummy.js?without-nonce>;rel=preload;as=script
-Link: </preload/resources/dummy.js?with-nonce>;rel=preload;as=script;nonce=abc
+Link: </preload/resources/dummy.js?from-header&without-nonce>;rel=preload;as=script
+Link: </preload/resources/dummy.js?from-header&with-nonce>;rel=preload;as=script;nonce=abc

third_party/blink/web_tests/external/wpt/preload/link-header-preload-srcset.tentative.html

@@ -11,16 +11,16 @@
 <script>
     window.addEventListener("load", t.step_func(function() {
         verifyPreloadAndRTSupport();
-        verifyNumberOfDownloads('resources/square.png?1x', 1);
-        verifyNumberOfDownloads('resources/square.png?2x', 0);
-        verifyNumberOfDownloads('resources/square.png?3x', 0);
-        verifyNumberOfDownloads('resources/square.png?base', 0);
-        verifyNumberOfDownloads('resources/square.png?200', 0);
-        verifyNumberOfDownloads('resources/square.png?400', 1);
-        verifyNumberOfDownloads('resources/square.png?800', 0);
-        verifyNumberOfDownloads('resources/square.png?150', 0);
-        verifyNumberOfDownloads('resources/square.png?300', 1);
-        verifyNumberOfDownloads('resources/square.png?600', 0);
+        verifyNumberOfDownloads('resources/square.png?from-header&1x', 1);
+        verifyNumberOfDownloads('resources/square.png?from-header&2x', 0);
+        verifyNumberOfDownloads('resources/square.png?from-header&3x', 0);
+        verifyNumberOfDownloads('resources/square.png?from-header&base', 0);
+        verifyNumberOfDownloads('resources/square.png?from-header&200', 0);
+        verifyNumberOfDownloads('resources/square.png?from-header&400', 1);
+        verifyNumberOfDownloads('resources/square.png?from-header&800', 0);
+        verifyNumberOfDownloads('resources/square.png?from-header&150', 0);
+        verifyNumberOfDownloads('resources/square.png?from-header&300', 1);
+        verifyNumberOfDownloads('resources/square.png?from-header&600', 0);
         t.done();
     }));
 </script>

third_party/blink/web_tests/external/wpt/preload/link-header-preload-srcset.tentative.html.headers

-Link: <resources/square.png?1x>; rel=preload; as=image; imagesrcset="resources/square.png?2x 2x, resources/square.png?3x 3x"
-Link: <resources/square.png?base>; rel=preload; as=image; imagesrcset="resources/square.png?200 200w, resources/square.png?400 400w, resources/square.png?800 800w"; imagesizes=400px
-Link: <resources/square.png?base>; rel=preload; as=image; imagesrcset="resources/square.png?150 150w, resources/square.png?300 300w, resources/square.png?600 600w"; imagesizes="(min-width: 300px) 300px, 150px"
+Link: <resources/square.png?from-header&1x>; rel=preload; as=image; imagesrcset="resources/square.png?from-header&2x 2x, resources/square.png?from-header&3x 3x"
+Link: <resources/square.png?from-header&base>; rel=preload; as=image; imagesrcset="resources/square.png?from-header&200 200w, resources/square.png?from-header&400 400w, resources/square.png?from-header&800 800w"; imagesizes=400px
+Link: <resources/square.png?from-header&base>; rel=preload; as=image; imagesrcset="resources/square.png?from-header&150 150w, resources/square.png?from-header&300 300w, resources/square.png?from-header&600 600w"; imagesizes="(min-width: 300px) 300px, 150px"